.item-enter {
  opacity: 0;
}
.item-enter-active {
  opacity: 1;
  transition: opacity 500ms ease-in;
}
.item-exit {
  opacity: 1;
}
.item-exit-active {
  opacity: 0;
  transition: opacity 500ms ease-in;
}
.div1 {
  background-color: #56a5f1;
  margin-top: 10px;
  margin-bottom: 10px;
  padding: 20px 0;
}